There are conventional inkjet recording devices known in the art that can record an image onto a recording medium by ejecting ink stored in an ink container from nozzles. In one of such inkjet recording devices, a new ink cartridge can be attached for replacement every time ink is consumed.
Japanese Utility Model Registration No. 3156861 discloses an ink cartridge that is detachably mountable in a cartridge-receiving section of an ink jet recording device. The ink cartridge has a detecting mechanism for optically allowing detection of a residual amount of ink. The detecting mechanism includes a movable bar that is pivotally movable about a fixed shaft, and a soft support cap. When ink stored in an ink bag is consumed, the ink bag shrinks. When the ink bag shrinks, the soft support cap also shrinks, which causes the movable bar to change its pivoting posture. Optically detecting the change in the pivoting posture of the movable bar makes it possible to detect that ink has been consumed in the ink cartridge.